Refrigerator evaporator



1957 H. LICHTENBERGER REFRIGERATOR EVAPORATOR 2 Sheets-Sheet 1 Filed Dec. 11, 1952 a 6g llzgtifkrzlegzr M m 1957 H. LICHTENBERGER 2,776,551

REFRIGERATOR EVAPORATOR Filed Dec. 11, 1952 2 Sheets-Sheet 2 United States Patent G REFRIGERATOR EVAPORATOR Harley Lichtenberger, Evansville, Ind, assignor, by inesne assignments, to Whirlpool-Seeger Corporation, a corporation of Delaware Application December 11, 1952, Serial No. 325,462

7 Claims. (Cl. 62-426) This invention relates generally to refrigerator evaporators and more specifically to improved refrigerator evaporators which will efficiently function during the refrigeration cycle or defrost cycle of a refrigerator.

It is an object of this invention to provide a refrigerator evaporator that will efficiently operate as an evaporator during the refrigeration cycle and which will operate rapidly and effectively during the defrost cycle so that the length of time required for defrosting is kept to a minimum.

It is another object of this invention to provide a refrigerator evaporator which can be defrosted without any substantial defrosting of any frozen food disposed within the confines of the evaporator.

It is a feature of this invention that a special reservoir is mounted or formed as part of the evaporator.

Other objects and features of this invention will be apparent upon a perusal of the following specification and drawings, of which:

Fig. 1 is a perspective view of one embodiment of an evaporator constructed according to this invention.

Fig. 2 is a perspective view of another embodiment of a refrigerator evaporator constructed according to this invention.

Fig. 3 is a side plan view of one embodiment of the special reservoir constructed according to this invention.

Fig. 4 is a cross sectional view of the reservoir shown in Fig. 3taken along the line 4-4.

Fig. 5 is a cross sectional side view of another embodiment of the special reservoir constructed according to this invention.

Fig. 6 is a cross sectional view of the special reservoir shown in Fig. 5 taken along the line 6-6.

The present embodiments are the preferred embodiments but it is to be understood that changes can be made in the present embodiments by one skilled in the art without departing from the spirit and scope of this invention.

Generally this invention comprises the forming of a horizontal base portion with wall portions attached thereto, and the forming or mounting of serpentine tubing in cooperation with the base and wall portions to form an evaporator. This invention further comprises the mounting or forming of a special reservoir on the underside of the base portion, and of connecting the special reservoir into the serpentine tubing arrangement. This invention further comprises the mounting of specific electrical heating means in thermal contact with the special reservoir.

To describe the invention in detail, reference is first made to Fig. 1. A sheet of metal 2 is formed with a horizontally disposed base portion and two vertical end walls. To the sheet 2 a serpentine tubing arrangement is mounted. This arrangement includes an inlet 8, a length of tubing 3 leading to reservoir 4, a length of serpentine tubing 9 leading from the reservoir 4 to the special reservoir 5, another length of serpentine tubing 10 leading from the special reservoir 5 to the reservoir 6, and a length of tubing 7 connected to the reservoir 6 and functioning as the outlet for the evaporator. These various litter ice tubings and reservoirs may be Welded to the sheet 2 or, as is well known in the art, the sheet 2 may be formed of two sheets bonded together with one or both sheets having the configurations of the various reservoirs and tubings stamped therein.

The embodiment shown in Fig. 2 comprises a sheet 20 formed with a horizontally disposed base portion and a vertically disposed back wall attached thereto. To the sheet 20 a length of tubing 26 is mounted. One end of the tubing as is connected to the inlet 27 and the other end of the tubing 26 is connected to the special reservoir 24. To the special reservoir 24 two lengths of serpentine tubing 23 and 25 are connected. The configuration of these lengths of tubing 23 and 25 may easily be seen in Fig. 2. The other ends of the tubings 23 and 25 are connected to the reservoir 22, and to the reservoir 22 a length of outlet tubing 21 is connected. As previously described in regard to Fig. l, the embodiment shown in Fig. 2 may also be formed of two sheets bonded together with one or both sheets having the configuration of the various reservoirs and tubings stamped therein. In the base portion of the sheet 2b a number of V-shaped depressions 28 are formed. Each of these depressions 28 has a minimum depth at one end thereof and progressively increases in depth from that end to the other end of the depression. At the ends of the depressions 28 having the maximum depth, a number of openings 29 are disposed. Thus any water collecting upon the upper surface of the base portion will drain along the depressions 23 and through the openings 29. When this evaporator is in normal use in a refrigerator, a drip tray (not shown) is disposed below the evaporator to collect the Water dripping from the evaporator.

The evaporators shown in Fig. l and 2 are intended to be mounted within a conventional refrigerator cabinet (not shown) near the upper portion thereof. The upper and rear portions of the inner liner of the refrigerator will then form part of the confines of the evaporator shown in Fig. l, and portions of the side and upper walls of the inner liner of the refrigerator will form part of the confines of the evaporator shown in Fig. 2. It is further intended, as is well known in the art, that the inlets 8 and 27 of the evaporator of Figs. 1 and 2 be connected to the outlets of conventional refrigerator condensers (not shown), and that the outlets 7 and 21 be connected to the inlets of conventional refrigerator compressors (not shown). It is further intended that the evaporator, and the remainder of the system (not shown) he charged with a suitable refrigerant, so that the inlets 8 and 27 will be liquid lines and the outlets 7 and 21 will be suction lines.

Referring now to Fig. 1 it can easily be seen that when the evaporator is connected as described above to a conventional refrigerator, liquid refrigerant will enter the inlet 8, flow through the tubing 3, flow through the reservoir 4, flow through the tubing 9, gravity fill and flow through the special reservoir 5, flow through the tubing if! to the reservoir 6. Some of the liquid refrigerant will collect within the reservoirs 5 and 6 and will remain therein. As the liquid refrigerant absorbs heat some of the liquid refrigerant will be heated to the point of its latent heat of vaporization and will then vaporize. This vapor will be withdrawn from the evaporator through the suction line. A similar operation will result when the evaporator shown in Fig. 2 is connected to a conventional refrigerator as described above. Thus because the special reservoir 24 is lower than the other parts of the evaporator, the force of gravity will cause liquid refrigerant to fill and be maintained Within the special reservoir 24.

Two embodiments of the special reservoirs 5 and 24 of Figs. 1 and 2 respectively are shown in Figs. 3 through 6. Either of the two embodiments shown in Figs. 3 through 6 may be used with either of the evaporators 3 shown in Figs. l and 2. Referring to Figs 3 and 4, the reservoir is shown as having a pan like portion 31 and a cover portion 30. If the evaporator is formed of a sheet with the tubing welded thereto. then the cover portion 36 would comprise part of that sheet and the pan portion 31 would be welded to the underside of the sheet, and the tubing would be welded to openings provided in the pan portion 31. If the evaporator is formed of two sheets, then as previously described, the pan portion 31 would be stamped into the lower sheet, and the tubing would be stamped in the lower sheet to connect with the pan portion 31. The lower portion of the pan portion 31 has curved channels formed longitudinally therein. Disposed within these channels is a U- shaped heating element 32. The circumference of the heating element 32 is such that when it is mounted in cooperation with the channels in the lower portion of the pan portion SE, at least one-fourth of the circumference of the heating element 32 is in thermal contact with the lower portion of the pan portion 31. The heating element 32 is of any well known type and may be connected to an electrical circuit (not shown) for power.

Referring to Figs. and 6 for a detailed description of the embodiment shown therein, the special reservoir is Constructed in a manner similar to that described above for the embodiment shown in Figs. 3 and 4. The reservoir comprises a pan portion 41 and a cover portion 30. The various tubings are connected into the pan portion 41. An opening is provided at one end of the pan 41. An electrical heating element 42 is inserted through the hole and is mounted in thermal con tact with the inner surfaces of the pan portion 41. The opening in the end of the pan portion 41 is sealed by member 44 which may be welded over the opening. A pair of conductors 45 project through the member 44 and are insulated therefrom and from each other by some material, such as fused glass. The ends of the pair of conductors 45 are connected to a pair of terminals 43 which provide an electrical current path from one of the conductors 45 through the heating element 42 and through the other conductor 45. To the ends of the pair of conductors 45, which are projecting from the member 44, an electrical circuit (not shown) may be connected for power for the electrical heater 42. It can easily be seen in Fig. 6 that the pan portion 41 is so shaped that at least one-fourth of the circumference of the heating element 42 is in thermal contact with the inner wall surfaces of the pan portion 41.

It can easily be seen that if power is applied to either of the embodiments shown in Figs. 3 through 6, heat will be efficiently conducted, in the one instance, from the heater 3?. through the walls of the pan portion 31 to the contents of the pan portion 31, and in the other instance, from the electrical heater 42 directly to the contents of the pan portion 41, and indirectly to the contents of the pan portion 41 through the walls of the pan portion 41 from the electrical heater 42.

To describe the operation of the embodiment shown in Fig. 1 reference is made thereto and it is assumed that either one of the embodiments shown in Figs. 3 to 6 is associated therewith since both of the embodiments shown in Figs. 3 through 6 accomplish the same result, that of heating the contents of the reservoir. As described previously, when the evaporator shown in Fig. l is connected in a conventional refrigerator (not shown), the evaporator will effectively cool any food placed within the confines of the evaporator. As is well known in the art, a conventional refrigerator through normal use will accumulate frost upon the surfaces of its evaporator which must be periodically removed to prevent any substantial reduction in the efliciency of the refrigerator. This invention comprises means for effectively accomplishing this purpose. As described previously, in normal use of the evaporator, liquid refrigerant will be disposed within the pan portion of the reservoir 5. Now, when the heating means are energized, the liquid refrigerant within the reservoir 5 will be heated, and the refrigerant will boil. The hot gases then formed will pass through the various convolutions of the evaporator and will heat the evaporator to cause any frost on the surfaces thereto to be melted. Specifically, part of the hot gases will be forced through the tubing 9, through the reservoir 4 and through the tubing 3 to melt any frost upon the surfaces adjacent thereto. Another portion of the hot gases will be simultaneously projected through the tubing 10 and the reservoir 6 to melt any frost upon the surfaces of the evaporator adjacent thereto. When defrosting of the evaporator is completed, the electrical heater is deenergized, the liquid refrigerant will cease boiling, the hot gases will cool and condense and by aid of the force of gravity will flow to the reservoir 5, and the refrigerator may again be operated in a normal rc' frigeration cycle.

The operation of the evaporator shown in Fig. 2 is similar to that shown in Fig. 1. When the liquid refrigerant disposed within the reservoir 24 is heated, a portion of the hot gases produced will be projected through the tubing 26. A second portion of the hot gases produced will be projected through the tubing 23 and a portion of the reservoir 22. A third portion of the hot gases produced will be projected through tubing 25 and the other portion of the reservoir 22. This will result in a melting of any frost disposed upon the various surfaces of the evaporator. The melted frost or defrost water produced by the above described operation will flow into the V-shaped depressions 28 along the length thereof and through the openings 29. When the defrost water has drained from the evaporator, the electrical heater may be deenergized, the hot gases will cool and condense and flow to the reservoir 24, and the refrigerator (not shown) in which this evaporator is mounted may again be operated on a normal refrigeration cycle.

It can thus be seen that this invention provides an evaporator which can be mounted within a refrigerator, which will efficiently operate as a refrigerator evaporator, and which may be rapidly and effectively defrosted to keep to a minimum the period of time required for the defrosting thereof. As can easily be seen, this is accomplished through unique structure which may rapidly heat the refrigerant to cause the refrigerant to boil, and to rapidly distribute the boiling refrigerant through the various parts of the structure.

Having described the invention, what is considered new and desired to be protected by Letters Patent is:

1. An evaporator for a refrigerator comprising a wall portion, a horizontally disposed base portion joined to said wall portion, a reservoir formed on the underside of said base portion, a length of serpentine tubing formed in one portion of said base portion and one portion of said wall portion, one end of said serpentine tubing connected to said reservoir substantially at the top thereof, second length of serpentine tubing formed in another portion of. said base portion, one end of said second length of serpentine tubing connected to said reservoir substantially at the top thereof, tithing means cooperating with said first and second lengths of serpentine tubing and said reservoir for permitting said lengths of serpentine tubing and said reservoir to be connectible in a refrigerator, so that liquid refrigerant is disposed in the lower portion of said reservoir when said evaporator is connected in a refrigerator, and an electric heating element in thermal contact with said lower portion of said reservoir so that any liquid refrigerant disposed in said lower portion of said reservoir is heated to form a gas and simultaneously projected through said first and second lengths of serpentine tubing when an electric current is conducted through said heating element.

2. An evaporator for a refrigerator comprising a horizontally disposed longitudinal base portion, a pair of wall portions, one of said wall portions joined at each end of said base portion, a reservoir formed on the underside of said base portion longitudinally across the center thereof and depending from said base portion, a length of serpentine tubing formed on said base portion on one side of said reservoir and said wall portion joined to said base portion on one side of said reservoir, one end of said length of serpentine tubing connected to said reservoir, 2. second length of serpentine tubing formed on said base portion on the other side of said reservoir and said wall portion joined to said base portion on said other side of said reservoir, one end of said second length of serpentine tubing connected to said reservoir, the other ends of said first and second lengths of serpentine tubing connectible in said refrigerator so that any liquid refrigerant present at said other ends of said first and second lengths of serpentine tubing will tend to flow into said reservoir, heater mean in thermal cooperation with said reservoir and operable to produce heat so that when liquid refrigerant is disposed within said reservoir said means are operable to heat said liquid refrigerant to a hot gas which will simultaneously flow through said first and second lengths of serpentine tubing.

3. An evaporator for a refrigerator comprising a hori- Zontally disposed longitudinal base portion, a wall portion joined at one end to said base portion, a reservoir formed on the underside of said base portion longitudinally across the center thereof and depending from said base portion, a length of serpentine tubing formed on said base portion on one side of said reservoir and on one side of said wall portion, one end of said length of serpentine tubing connecting to said reservoir substantially at the top thereof, a second length of serpentine tubing formed on said base portion on the other side of said reservoir and on the other side of said wall portion, one end of said second length of serpentine tubing connected to said reservoir substantially at the top thereof, the other ends of said first and second lengths of serpentine tubing connected to an outlet tube, an inlet tube formed on said base portion and a part of said Wall portion, said inlet tube connected to said reservoir, said inlet and outlet tubes connectible in said refrigerator so that any liquid refrigerant present at said inlet and outlet tubes will tend to flow into said reservoir, electric heater means in thermal cooperation with a lower portion of said reservoir and operable to produce heat so that when liquid refrigerant is disposed within said reservoir said means are operable to heat said liquid refrigerant to a hot gas which will simultaneously flow through said first and second lengths of serpentine tubing when an electric current is conducted through said heating element.

4. An evaporator for a refrigerator comprising a horizontally disposed longitudinal base portion, a pair of wall portions, one of said wall portions joined at each end of said base portion, a reservoir formed on the underside of said base portion longitudinally across the center thereof and depending from said base portion, a length of serpentine tubing formed on said base portion on one side of said reservoir and said wall portion joined to said base portion on one side of said reservoir, one end of said length of serpentine tubing connected to said reservoir substantially at the top thereof, a second length of serpentine tubing formed on said base portion on the other side of said reservoir and said wall portion joined to said base portion on said other side of said reseiwoir, one end of said second length of serpentine tubing connected to said reservoir substantially at the top thereof, the other ends of said first and second lengths of serpentine tubing connectable in said refrigerator by tubing means so that any liquid refrigerant present at said other ends of said first and second lengths of serpentine .tubing will tend to flow into said reservoir, said reservoir having an arcuate shaped channel formed therein to extend about the lower portion there-of, a generally U-shaped electrical heater mounted in thermal contact with a lower portion of said reservoir in said channel, said electrical heater operable to produce heat so that when liquid refrigerant is disposed within the lower portion of said reservoir said electrical heater is operable to heat said reservoir to in turn heat said liquid refrigerant to a hot gas which will simultaneously be projected and flow through said first and second lengths of serpentine tubing, when an electric current is conducted through said heating element.

5. An evaporator for a refrigerator comprising a horizontally disposed longitudinal base portion, a pair of wall portions, one of said wall portions joined at each end of said base portions, a reservoir formed on the underside of said base portion longitudinally across the center thereof and depending from said base portion, a length of serpentine tubing formed on said base portion on one side of said reservoir and said wall portion joined to said base portion on one side of said reservoir, one end of said length of serpentine tubing connected to said reservoir substantially at the top thereof, a second length of serpentine tubing formed on said base portion on the other side of said reservoir and said wall portion joined to said base portion on said other side of said reservoir, one end of said second length of serpentine tubing connected to said reservoir substantially at the top thereof, the other ends of said first and second lengths of serentine tubing connectable by tubing means in said refrigerator so that any liquid refrigerant present at said other ends of said first and second lengths of serpentine tubing will tend to flow into said reservoir, an electrical heater mounted within said reservoir in thermal contact therewith, said electrical heater being generally U-shaped and having insulated terminals connected to the ends thereof, said terminals extending from a lower portion of said reservoir, said electrical heater operable to pro duce heat so that when liquid refrigerant is disposed with in said reservoir said electrical heater is operable to directly heat said liquid refrigerant .to a hot gas and to indirectly heat said liquid refrigerant to a hot gas through the Walls of said reservoir in thermal contact with said electrical heater, whereby the liquid refrigerant will be heated to a hot gas which will simultaneously be projected and flow through said first and second lengths of serpentine tubing when an electric current is conducted through said heating element.

6. An evaporator for a refrigerator comprising a hori zontally disposed longitudinal base portion, a wall portion joined at one end of said base portion, a reservoir formed on the underside of said base portion longitudinally across the center thereof and depending from said base portion, a length of serpentine tubing formed on said base portion on one side of said reservoir and on one side of said wall portion, one end of said length of serpentine tubing connected to said reservoir substantially at the top thereof, a second length of serpentine tubing formed on said base portion on the other side of said reservoir and on the other side of said wall portion, one end of said second length of serpentine tubing connected to said reservoir substantially at the top thereof, the other ends of said first and second lengths of serpentine tubing connected to an outlet tube, an inlet tube formed on said base portion and a part of said wall portion, said inlet tube connected to said reservoir, said inlet and outlet tubes connectable by tubing means in said refrigerator so that any liquid refrigerant present at said inlet and outlet tubes will tend to flow into said reservoir, said reservoir having an arcuate shaped channel formed therein to extend about the lower portion thereof, a generally U-shaped electrical heater mounted in thermal contact with a lower portion of said reservoir in said channel, said electrical heater operable to produce heat so that when liquid refrigerant is disposed Within said reservoir said electrical heater is operable to heat said reservoir to in turn heat said liquid refrigerant to a hot gas which will simultaneously be projected and flow through said first and second lengths of serpentine tubing when an electric current is conducted through said heating element.

7. An evaporator for a refrigerator comprising a horizontally disposed longitudinal base portion, a wall portion joined to said base portion, a reservoir formed on the underside of said base portion longitudinally across the center thereof and depending from said base portion, a length of serpentine tubing formed on said base portion on one side of said reservoir and on one side of said wall portion, one end of said length of serpentine tubing connected to said reservoir substantially at the top thereof, a second length of serpentine tubing formed on said base portion on the other side of said reservoir and on the other side of said Wall portion, one end of said second length of serpentine tubing connected to said reservoir substantially at the top thereof, the other ends of said first and second lengths of serpentine tubing connected to an outlet tube, an inlet tube formed on said base portion and a part of said wall portion, said inlet tube connected to said reservoir, said inlet and outlet tubes connectable by tubing means in said refrigerator so that any liquid refrigerant present at said inlet and outlet tubes will tend to flow into said reservoir, an electrical heater mounted within said reservoir in thermal contact therewith, said electrical heater being generally U-shaped and having insulated terminals connected to the ends thereof, said terminals extending from said reservoir, said electrical heater operable to produce heat so that when liquid refrigerant is disposed within and in thermal contact with the lower part of said reservoir said electrical heater is operable to directly heat said liquid refrigerant to a hot gas and to indirectly heat said liquid refrigerant to a hot gas through the Walls of said reservoir in thermal contact with said electrical heater, whereby the hot gas produced ii-ill simultaneously be projected and flow through said first and second lengths of serpentine tubing when an electric current is conducted through said heating element.

References Cited in the file of this patent UNITED STATES PATENTS 2,00t,323 Dick May 14, 1935 2,008,628 Ruff July 16, 1935 2,591,109 Wade Apr. 1, 1952 2,635,439 Philipp Apr. 21, 1953 2,654,226 Duncan Oct. 6, 1953 2,665,567 King Jan. 12, 1954 

